1. Technical Field
The present invention relates to a medium transportation device including a transportation section that transports a long medium and a winding section that winds the medium transported by the transportation section, and a recording apparatus.
2. Related Art
For example, a medium transportation device is disclosed in JP-A-2004-107021 (for example, FIG. 1 or the like), which includes a transportation section (a grip section) that transports a long recording medium sent out from a roll-shaped medium (for example, a roll paper) charged in a feeding section toward a downstream side while being clamped between a driving roller and a driven roller (a pinch roller), and a winding section (a winding scroller) that winds the recording medium transported by the transportation section toward the downstream side in a roll shape. A recording apparatus including the medium transportation device includes a recording section that performs recording (printing) on a portion of the recording medium on a medium support section (a platen) disposed on a downstream side from the transportation section. The recording medium, which is discharged along a paper guide after the printing is performed, is wound around the winding section while tension is applied to the recording medium by pressing a tension roller in a portion of the recording medium between the paper guide and the winding section.
Incidentally, there is a case where the recording medium is wound around the winding section in a position deviated in a width direction relative to a position clamped by the transportation section. In this case, if a biased force is propagated to an upstream side during the time of winding with the deviation of a winding position of the winding section in a width direction, the recording medium is deviated by the propagated force in the width direction in the transportation section and this causes skewing or meandering of the recording medium between the transportation section and the winding section.
For example, techniques for increasing a coefficient of friction of all or a part of a periphery of a roller (a transportation roller or a platen roller) configuring a transportation section are disclosed in JP-A-2007-245599 (for example, FIG. 5 or the like), JP-A-8-174928 (for example, paragraph [0010] or the like) and JP-A-4-270672 (for example, paragraph [0010], FIG. 2 or the like). For example, in JP-A-2007-245599, a friction applying member is formed in the transportation roller. In addition, in JP-A-8-174928, for example, a coefficient of friction of a surface of a rubber elastic body with the recording medium is a value of 0.4 to 0.6 obtained by coating a fluorine resin on the surface of the rubber elastic body coated on a core material of the platen roller. In addition, in JP-A-4-270672, a correcting roller is provided in which rubber rollers having a relatively large coefficient of friction are mounted on both ends thereof, and a belt skew correcting unit is provided which serves as a guide roller applying tension.
In the medium transportation device as described in JP-A-2004-107021, in which the winding section winds the recording medium, when the recording medium is biased and wound as described above, even if the deviation of the recording medium in the width direction is suppressed by the frictional resistance in a position of the transportation section away from the winding section on the upstream side, a large frictional resistance force is necessary to suppress the deviation thereof in the position of the transportation section on the upstream side, because a portion of the recording medium is largely deviated on the downstream side. In contrast, if the coefficient of friction of the roller is remarkably large, there is a concern that a catch thereon may occur during the time of transporting due to the remarkably large frictional resistance force of the recording medium received from the roller. If the catch of this type occurs, there is a problem in that the recording medium is inclined or the positional accuracy of the transportation is reduced without being transported with a required amount of the transportation.
Therefore, even if the coefficient of friction of all or some of the rollers is increased as described in JP-A-2007-245599, JP-A-8-174928 and JP-A-4-270672, it is difficult to sufficiently suppress skewing or meandering of the recording medium between the transportation section and the winding section, caused by biasing of the winding position of the recording medium in the winding section in a direction (width direction) intersecting the transport direction.
As a method to avoid such a problem and to suppress the skewing or the meandering of the recording medium between the transportation section and the winding section, the inventors of the invention found that a method is effective in which a medium support section (a discharging support section) for guiding the recording medium which is transported on a support surface between the transportation section and the winding section on the downstream side thereof is provided, and an elastic member having a frictional surface having a coefficient of friction with the recording medium greater than a coefficient of friction of the support surface with the recording medium is fixed to an end portion of the medium support section on the downstream side in the transport direction so as to extend in a width direction. According to the method in which the recording medium is transported so as to slide on the frictional surface of the elastic member, it is possible to suppress the skewing or the meandering of the recording medium between the transportation section and the winding section by suppressing the deviation of the recording medium in the width direction due to the relatively high coefficient of friction of the frictional surface with the recording medium.
However, in the method, there is a concern that a frictional force of the frictional surface of the elastic member fixed to the end portion of the support section on the downstream side in the transport direction so as to extend in the width direction is too excessive, the catch of the recording medium occurs during the time of transporting of the recording medium, the transport speed is unstable and then the positional accuracy of the transportation is reduced.